Control of luciferase synthesis in a newly isolated strain of Photobacterium leiognathi

Abstract

In previous studies with luminous bacteria of all different species it has been reported that the synthesis of luciferase is autoinducible: during growth at low cell densities synthesis is effectively repressed while after induction, at higher cell densities, the rate of synthesis of enzyme is up to five times the growth rate. In this paper we report on newly isolated strains of Photobacterium leiognathi which show continued luciferase synthesis irrespective of the cell density. The specific synthesis rate may nevertheless differ from the rate of growth and depends on the luciferase content of the inoculated cells. A ratio of 1 was established for cells having a maximum luciferase content varying to a ratio of about 2 for cells that contained only 1% of the maximum.

Regulation of Bioluminescence in Photobacterium leiognathi Strain KNH6

“…3). It was previously reported that certain Photobacterium isolates did not display cell density-dependent regulation of luminescence (7,9); however, study of the regulation of light production in these and other luminescent Photobacterium strains at the genetic level was hampered by a lack of tools. In the present study, we adapted several genetic tools, previously developed for use in V. fischeri, for use in KNH6.…”

“…They have been isolated from seawater samples as well as from eukaryotic hosts (2,7,8), and culture-based studies have indicated that Photobacterium strains vary in whether cell density-based signaling is used for regulatory control of luminescence (9). However, despite these interesting observations, to our knowledge, regulation of light production in Photobacterium species has not been studied genetically without the use of transgenic Escherichia coli.…”

“…These relatively recent studies have focused mainly on a few model organisms, particularly Vibrio harveyi (Vibrio campbellii) and Vibrio fischeri (Aliivibrio fischeri), and have contributed immensely to our understanding of bacterial pheromone signaling or quorum sensing (3)(4)(5). However, it is known that in marine habitats, luminous bacteria are widely distributed (1) and can be found free living as well as host associated (6), and it has been observed that certain isolates of Photobacterium leiognathi do not appear to display cell density-dependent regulation of luminescence (7). Taken together, these observations suggest that the regulation, nature, and ecological functions of bioluminescence are likely diverse.…”

An Evaluation of the PCB-TOX-SPOT Water Toxicity Test

“…The TOX-SPOT assay uses naturally bioluminescent Photobacterium leiognathi (Katznelson and Ulitzur, 1977) and is commercially available through Checklight Ltd, (Figure 2-1). The premise of the assay is that the inhibition of bacterial light output is an indication of the presence of a toxic chemical.…”

ORGANIZATION and REGULATION OF BACTERIAL LUMINESCENCE GENES

“…Luciferase and the fatty acid reductase enzymes are induced at high cell density in some strains of P. leiognathi and P. phosphoreum (Wall et al, 1984;Delong et al, 1987;Illarionov and Protopopova, 1987), but luciferase expression is constitutive in others (Katznelson and Ulitzur, 1977;Watanabe and Hastings, 1986). The putative autoinducers of P. leiognathi and P. phosphoreum strains that exhibit induction of luminescence have not been characterized, but substantial evidence has been obtained for the production of an autoinducer by P. leiognathi strains from light organs of leiognathid fish (Dunlap, 1984a).…”